SS3.17 Global Mercury Cycling: From Natural to Anthropogenic Sources
Date: Tuesday, June 11, 2002
Time: 10:30:00 AM
Location: Carson C
 
GustinMS, University of Nevada, Reno, USA, msg@unr.nevada.edu
Benesch, J, A, University of Nevada, Reno, USA, 
Frescholtz, T, F, University of Nevada, Reno, USA, 
Schorran, D, S, Desert Research Institute, Reno, USA, 
Johnson, D, W, University of Nevada, Reno, USA, 
Lindberg, S, E, University of Nevada, Reno, USA, 
Coleman, J, S, Desert Research Institute, Reno, USA, 
 
FORESTS AS SOURCES OF NEW HG TO ECOSYSTEMS
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The role of vegetation in the biogeochemical cycle of (mercury) Hg was investigated using Quaking Aspen at three scales. Single plants were studied using a gas exchange system to understand the patterns in daily uptake and emission of atmospheric Hg. Multiple plant exposures investigated uptake of atmospheric Hg as a function of time, soil and air Hg concentrations. Experiments utilizing 100 aspen in two replicate mesocosms investigated Hg fluxes between soils, plants and the atmosphere. Results indicate that nearly 100% of Hg in foliar tissue is derived from the atmosphere and that tissue concentration increased with time and as a function of air exposure concentrations. At high soil Hg concentrations and low air concentrations plants can act as a source of mercury to the atmosphere, however the role of vegetation as a net sink is dominant. Our data demonstrate that vegetation can act as a pathway for new mercury to be transferred from the atmosphere to terrestrial, and ultimately, aquatic ecosystems.